The term "payday" also represents the day employees are paid
for their earnings from the pay period which ended ten (10) days previous.
Payday is the day employees take constructive receipt of their wages.

The first payday in the calendar year for W-2 reporting is January 10th,
but the wages and salaries being paid on January 10th were earned December
16th - 31st. Even though it was earned in the previous calendar year, it
is reported on the following year's W-2 Form because employees do not receive
their pay until January 10th